Sound conduction in the ear requires an intact ossicular chain (the bones in the middle ear). Because of chronic infection, trauma or cholesteatoma (skin in the middle ear) the ossicular chain may become eroded. This causes a 20-55 decibel conductive hearing loss.
The normal ossicular chain functions as an efficient lever system that transfers sound from the tympanic membrane to cochlear fluids. Interruption of the ossicular chain can be caused by erosion, most commonly at the long process or lenticular process of the incus.
Previous methods of repairing such discontinuities primarily involved the implantation of prosthetic elements. A wide variety of forms of implants must be made available. It has proven difficult to accurately position the implants which often slip, become dislodged or extrude through the eardrum. Success of the implants, in terms of closing the air-bone gap so as to provide effective hearing, is limited. It has alternatively been proposed to manually form a linking section out of a bone cement or other self-hardening material and using it to bridge the disruption in the ossicular chain.